Modify the NaCl_page_alloc_hint function to use VirtualQuery to check

src/trusted/service_runtime/win/sel_memory.c

Index: src/trusted/service_runtime/win/sel_memory.c
===================================================================
--- src/trusted/service_runtime/win/sel_memory.c	(revision 6420)
+++ src/trusted/service_runtime/win/sel_memory.c	(working copy)
@@ -24,6 +24,31 @@
 
 #define MSGWIDTH  "25"
 
+#if NACL_ARCH_CPU_32_BITS

[Mark Seaborn, 2011/08/16 17:34:10]

As before.

[bbudge, 2011/08/16 19:46:22]

Done.

+
+int   NaCl_find_sandbox_memory(void   **p,

[Mark Seaborn, 2011/08/16 17:34:10]

Can you put a comment in to say that the purpose of this is to look for a region
reserved by the parent process on our behalf?

[bbudge, 2011/08/16 19:46:22]

Done.

+                               size_t num_bytes) {
+  SYSTEM_INFO sys_info;
+  MEMORY_BASIC_INFORMATION mem;
+  char* start;

[Mark Seaborn, 2011/08/16 17:34:10]

Nit: " *" rather than "* "

[bbudge, 2011/08/16 19:46:22]

Done.

+
+  GetSystemInfo(&sys_info);
+  start = sys_info.lpMinimumApplicationAddress;
+  while (VirtualQuery((LPCVOID)start, &mem, sizeof(mem))) {

[Mark Seaborn, 2011/08/16 17:34:10]

I'd suggest checking that the return value is either 0 or sizeof(mem), just in
case.  i.e. CHECK(result == sizeof(mem)) after.

[bbudge, 2011/08/16 19:46:22]

Done.

+    if (mem.State == MEM_RESERVE && mem.RegionSize == num_bytes) {
+      VirtualFree(start, 0, MEM_RELEASE);

[Mark Seaborn, 2011/08/16 17:34:10]

Please check return value.  You can use LOG_FATAL on error.

[bbudge, 2011/08/16 19:46:22]

Done.

+      *p = start;
+      return 0;
+    }
+    start += mem.RegionSize;
+    if ((LPVOID)start > sys_info.lpMaximumApplicationAddress)

[Mark Seaborn, 2011/08/16 17:34:10]

Minor nit: maybe '>='?

[bbudge, 2011/08/16 19:46:22]

Done.

+      break;
+  }
+  return -ENOMEM;
+}
+
+#endif  /* NACL_ARCH_CPU_32_BITS */
+
 /*
  * NaCl_page_free: free pages allocated with NaCl_page_alloc.
  * Must start at allocation granularity (NACL_MAP_PAGESIZE) and
@@ -48,8 +73,7 @@
 }
 
 
-static
-int   NaCl_page_alloc_hint(void    **p,
+int   NaCl_page_alloc_at_addr(void    **p,
                            size_t  num_bytes) {
   SYSTEM_INFO sys_info;
 
@@ -151,7 +175,7 @@
     *p = addr;
     return 0;
  retry:
-    NaClLog(2, "NaCl_page_alloc_hint: retrying w/o hint\n");
+    NaClLog(2, "NaCl_page_alloc_at_addr: retrying w/o hint\n");
     hint = NULL;
   }
 
@@ -161,7 +185,7 @@
 int   NaCl_page_alloc(void    **p,
                       size_t  num_bytes) {
   *p = NULL;
-  return NaCl_page_alloc_hint(p, num_bytes);
+  return NaCl_page_alloc_at_addr(p, num_bytes);
 }
 
 /*
@@ -203,7 +227,7 @@
 
     NaClLog(LOG_INFO, "NaCl_page_alloc_randomized: hint 0x%"NACL_PRIxPTR"\n",
             (uintptr_t) *p);
-    neg_errno = NaCl_page_alloc_hint(p, size);
+    neg_errno = NaCl_page_alloc_at_addr(p, size);
     if (0 == neg_errno) {
       break;
     }
@@ -213,7 +237,7 @@
             "NaCl_page_alloc_randomized: failed (%d), dropping hints\n",
             -neg_errno);
     *p = 0;
-    neg_errno = NaCl_page_alloc_hint(p, size);
+    neg_errno = NaCl_page_alloc_at_addr(p, size);
   }
   return neg_errno;
 }